Transportable water storage system

ABSTRACT

A transportable liquid storage system includes a plurality of silos, each adapted to be transported in a horizontal transport orientation and moved to a vertical operating orientation at the work site. The silos are arranged in at least two adjacent rows, and each silo is releasably and rigidly attached to all silos adjacent thereto such that the plurality of silos forms a rigid silo structure, and an outlet port on each water silo is connected to a conduit, the conduit having a discharge at a selected location. The silos include an overflow chamber at a top end thereof to allow each silo to fill to capacity on uneven ground, and a hollow base which facilitates leak containment and detection.

FIELD OF THE INVENTION

This invention is in the field of water storage and in particular atransportable water storage system with a large capacity.

BACKGROUND OF THE INVENTION

In some industrial applications, very large quantities of liquid arerequired at temporary work sites. For example in petroleum oil and gasrecovery operations, it is common practice to fracture an undergroundformation by injecting liquid comprising water and various chemicals athigh pressure into the formation. Formation fracturing operations,commonly called fracking, can require very large amounts of water, whichmust be gathered and stored in a temporary tank set up at the work site.Such fracking operations can require on site storage of one or even twomillion US gallons of water.

It is known to provide large open top tanks by erecting walls and layinga liner membrane over the ground inside the walls and up over the walls.Such open tanks can provide the required storage capacity, however aresubject to leaks. A leaking liner may allow a large quantity of thecontained liquid to leak into the ground, and since the contained liquidtypically contains undesirable materials, significant groundcontamination may occur undetected. Emptying these large tanks withoutspillage is also problematic.

Alternatively large metal tanks are transported to the work site wherethey are filled with water for use in the fracking operation. The tankstypically have a capacity of about 500 barrels or 21,000 US gallons andat the well site these tanks are placed on the ground eitherhorizontally or vertically. The horizontal tanks typically have wheelsmounted on a rear end thereof and are simply towed into position at thewell site. About 50 of these tanks are then required to hold the onemillion US gallons required for a typical fracking operation. The areaavailable at work site for placing these tanks is limited and becomesvery crowded.

Horizontal orientation occupies considerably more of the available area,than vertical orientation, however vertical orientation typicallyrequires specialized trailers or cranes to move the tanks, commonlycalled silos because of their vertical orientation, from the horizontalorientation required for transport, to the vertical orientation. Asignificant problem with vertical orientation is stability, as avertical silo rests on a relatively small area provided by the end ofthe silo. When empty especially, they are susceptible to be beingknocked over by high winds or accidental contact with other equipmentmoving around in the crowded work area.

Periodically such tanks must be cleaned to remove sediment and the like,typically requiring people to enter the tank.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a transportableliquid storage system that overcomes problems in the prior art.

In a first embodiment the present invention provides a transportableliquid storage system comprising a plurality of silos, each silo adaptedto be moved on a transport vehicle in a horizontal transport orientationto a work site and moved to a vertical operating orientation at the worksite with a silo base resting on the ground. The silos are arranged inat least two adjacent rows, and each silo is releasably and rigidlyattached to all silos adjacent thereto such that the plurality of silosforms a substantially rigid silo structure, and an outlet port on eachwater silo is connected to a conduit, the conduit having a discharge ata selected location.

In a second embodiment the present invention provides a water siloapparatus adapted to be moved on a transport vehicle in a horizontaltransport orientation to a work site and moved to a vertical operatingorientation at the work site. The apparatus comprises an elongate mainchamber with an outlet port in a lower portion thereof. A hollow base isattached to a lower end of the main chamber, wherein an entirety of thelower end of the main chamber rests on the hollow base when in thevertical operating position such that liquid leaking from the lower endof the main chamber collects in the hollow base, and a liquid detectoris located in the hollow base and is operative to send a leak signal toa leak indicator when liquid is detected in the hollow base. An overflowchamber extends upward from a top end of the main chamber, the overflowchamber having a cross-sectional area that is less than about 20% of across-sectional area of the main chamber, and a vent opening is providedin an upper portion of the overflow chamber.

The transportable liquid storage system provides a plurality of liquidstorage silos locked together in a silo structure that has considerablestability, which can be enhanced with folding stabilizer legs. A largequantity of liquid can thus be stored in a relatively small area at thework site. An overflow chamber allows the main chamber of each silo inthe silo structure to be filled to capacity when the silos are on unevenground maximizing the storage capacity of the structure. The overflowchamber also facilitates aeration of the liquid in the silo ifnecessary. The silos can include a removable hollow base which containsand detects leaks, and facilitates repairs. Scrubbers can facilitatecleaning of the silo interiors.

BRIEF DESCRIPTION OF THE DRAWINGS

While the invention is claimed in the concluding portions hereof,preferred embodiments are provided in the accompanying detaileddescription which may be best understood in conjunction with theaccompanying diagrams where like parts in each of the several diagramsare labeled with like numbers, and where:

FIG. 1 is a schematic top view of an embodiment of a transportable waterstorage system of the present disclosure.

FIG. 2 is a schematic side view of the embodiment of FIG. 1.

FIG. 3 is a schematic side view of a silo on a transport vehicle in ahorizontal orientation and being moved to a vertical operatingorientation at a work site.

FIG. 4 is a schematic cut-away side view of a silo of the embodiment ofFIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1 and 2 schematically illustrate an embodiment of a transportablewater storage system 1 of the present disclosure. The system 1 comprisesa plurality of water silos 3, each silo 3, as schematically illustratedin FIG. 3, adapted to be moved on a transport vehicle 5 in a horizontaltransport orientation to a work site and moved to a vertical operatingorientation at the work site with a silo base 7 resting on the ground 9.

The silos 3 are arranged in at least two adjacent rows, and each silo 3is releasably and rigidly attached to all silos 3 adjacent thereto byupper and lower releasable locking devices 11 such that the plurality ofsilos 3 forms a substantially rigid silo structure. In the illustratedsystem 1 locking device comprises a first lock mechanism 11A on a firstsilo and a corresponding second lock mechanism 11B on an adjacent secondsilo, and the first lock mechanism 11A is adapted to releasably engagethe second lock mechanism 11B. It is contemplated that the lockingdevices 11 could be provided by a variety of mechanisms known in theart, as an example FIG. 3 schematically illustrates the first lockmechanism 11A as a hook connected to an over-centering lever that isengageable with the second lock mechanism 11B provided by a loop.

Orienting the silos 3 vertically reduces the area required at theworksite but vertical silos, especially when empty, have significantstability problems. Locking the silos 3 together to form the silostructure greatly increases the stability of the structure compared to alone silo 3 resting on its base 7. Stability is further increased byproviding stabilizer legs 13 movably mounted to the silos 3 such thatthe stabilizer legs 13 movable from a stored position P1 adjacent to awall of the silos 3 to an operating position P2 extending outward fromthe silos 3 and outward from the silo structure and contacting theground 9.

An outlet port 15 on each water silo 3 is connected through a valve 17to a conduit 19 and the conduit 19 has a discharge 21 at a selectedlocation where the stored liquid will be used at the work site. An issuethat must be dealt with in many situations where the system will beused, such as in formation fracturing operations at well sites, is thatthe liquid will be drawn out very quickly, and so quite large ventopenings are required at the top of each silo 3 to allow air to enterthe silo as liquid is drawn off. Often all the valves 17 on the silostructure will be open to allow the liquid to drawn off quickly at thedischarge 21. When the silo structure is placed on uneven ground, somesilos will be higher than some others such that when the valves are allopen, liquid will flow from the higher silo to a lower silo and couldspill out the vents.

To avoid this and allow each silo 3 to be filled to capacity each silo 3comprises a main chamber 23 and an overflow chamber 25 extending upwardfrom a top end of the main chamber 23. The overflow chamber 25 is muchsmaller than the main chamber 23, with a cross-sectional area that isless than about 20% of the cross-sectional area of the main chamber 23,as seen in the top view of FIG. 1.

FIG. 2 shows the silos 3 located on ground 9 that slopes slightly upwardfrom left to right, such that each silo is higher than the silo 3 to theleft thereof. Thus when the outlet ports 15 on first and second silos3A, 3B are connected through respective valves 17 to the conduit 19 atthe same time such that liquid flows between the first and second silos,the first liquid level 27A in the first silo 3A on higher ground is at atop of the main chamber 23A, and the second liquid level 27B in thesecond silo 3B on lower ground is in the overflow chamber 25B. The mainchamber 23 on each silo can thus be filled to capacity. A large ventopening 29 can be provided in an upper portion of the overflow chambers25 to allow for air movement into and out of the silo 3 when filling anddraining the silo.

FIG. 4 schematically illustrates the water silo 3. In some applicationsit will be desired to add air to the liquid in the silos 3, such as whenstoring water returned from a well during fracturing operations. Thesilos 3 illustrated comprise an aeration conduit 31 extending from alower portion of the main chamber 23 to an aeration chamber locatedabove the main chamber 23, and conveniently provided by the overflowchamber 25. A pump 33 is operative to pump liquid from the lower portionof the main chamber 23 into the aeration/overflow chamber 25 above alevel of liquid 27 in the chamber 25 such that the liquid contacts theair above the liquid, as is desired for aeration purposes. Air can alsobe pumped into the lower portions of the main chamber 23 and rise to theaeration overflow chamber 25 and escape out through the vent opening 29.The overflow chamber 25 thus conveniently provides an air pocket toallow for aeration through the aeration conduit 31 as well as a surfacefrom which air pumped into liquid can bubble up through to the adjacentvent opening 29.

At times it may be desirable to draw liquid out of the silo 3 at ahigher level, such as to avoid sediment that may have formed in thebottom of the silo. The silo 3 in FIG. 4 thus has a lower outlet port15A and an upper outlet port 15B above the lower outlet port 15A. Tofacilitate emptying the silo 3 completely, and to facilitate removal ofsediment during cleaning, the floor 35 of the main chamber 23 of thesilo 3 slopes to the lower outlet port 15A.

A hollow base 7 is attached to a lower end of the main chamber 23. Theentire lower end of the main chamber 23 rests on the hollow base 7 whenin the vertical operating position such that liquid leaking from thelower end of the main chamber 23 collects in the hollow base 7 where aliquid detector 37 is located and operative to send a leak signal to aleak indicator 39 when liquid is detected in the hollow base 7. Thehollow base 7 is fastened to the lower end of the main chamber 23 bybolts or the like so the base is removable to provide access to repairthe lower end of the main chamber 23 if a leak is detected.

To facilitate cleaning the silos, lower and upper scrubbers 41A, 41B areoperative to direct pressurized streams of liquid on corresponding lowerand upper portions of the inner surface of the main chamber 23.Typically such scrubbers 41 will comprises a plurality of rotatablenozzles 43, and a high pressure liquid source 45 connected to thenozzles 43 to rotate the nozzles and provide the pressurized stream ofliquid.

The transportable liquid storage system 1 provides a plurality of liquidstorage silos locked together in a silo structure that has considerablestability, which can be enhanced with folding stabilizer legs 13. Theoverflow/aeration chamber 25 allows the main chamber of each silo 3 inthe silo structure to be filled to capacity when the silos are on unevenground and also facilitates aeration of the liquid in the silo ifnecessary.

The hollow base 7 provides leak detection and containment to preventundetected contamination of the ground at the work site. Scrubbers 41can be provided to clean the silo interiors, with a silo floor 35sloping to the outlet port 15 so sediment and the like will flow to theoutlet port 15.

The foregoing is considered as illustrative only of the principles ofthe invention. Further, since numerous changes and modifications willreadily occur to those skilled in the art, it is not desired to limitthe invention to the exact construction and operation shown anddescribed, and accordingly, all such suitable changes or modificationsin structure or operation which may be resorted to are intended to fallwithin the scope of the claimed invention.

1. A transportable liquid storage system comprising: a plurality ofsilos, each silo adapted to be moved on a transport vehicle in ahorizontal transport orientation to a work site and moved to a verticaloperating orientation at the work site with a silo base resting on theground; wherein the silos are arranged in at least two adjacent rows,and each silo is releasably and rigidly attached to all silos adjacentthereto such that the plurality of silos forms a substantially rigidsilo structure; and wherein an outlet port on each water silo isconnected to a conduit, the conduit having a discharge at a selectedlocation.
 2. The system of claim 1 wherein each silo is releasably andrigidly attached to all silos adjacent thereto by upper and lowerreleasable locking devices mounted on the silos.
 3. The system of claim2 wherein each locking device comprises a first lock mechanism on afirst silo and a corresponding second lock mechanism on an adjacentsecond silo, and wherein the first lock mechanism is adapted toreleasably engage the second lock mechanism.
 4. The system of claim 1further comprising a valve at an outlet port of each silo, and whereinthe conduit network is connected to each valve.
 5. The system of claim 1further comprising at least one stabilizer leg movably mounted to atleast one silo, the at least one stabilizer leg movable from a storedposition adjacent to a wall of the at least one silo to an operatingposition extending outward from the at least one silo and outward fromthe silo structure and contacting the ground.
 6. The system of claim 1wherein each silo comprises a main chamber and an overflow chamberextending upward from a top end of the main chamber, the overflowchamber having a cross-sectional area that is less than across-sectional area of the main chamber, and wherein the outlet portson first and second silos are connected to the conduit at the same timesuch that liquid flows between the first and second silos, and such thata first liquid level in the first silo on higher ground is at a top ofthe main chamber, and such that a second liquid level in the second siloon lower ground is in the overflow chamber.
 7. The system of claim 6wherein the cross-sectional area of the overflow chamber is less thanabout 20% of the cross-sectional area of the main chamber.
 8. The systemof claim 6 comprising a vent opening in an upper portion of the overflowchamber.
 9. The system of claim 6 wherein each silo comprises anaeration conduit extending from a lower portion of the main chamber toan aeration chamber located above the main chamber, and a pump operativeto pump liquid from the lower portion of the main chamber into theaeration chamber above a level of liquid in the aeration chamber. 10.The system of claim 9 wherein the aeration chamber is provided by theoverflow chamber.
 11. The system of claim 1 wherein at least one silocomprises a main chamber and a hollow base attached to a lower end ofthe main chamber, and wherein an entirety of the lower end of the mainchamber rests on the hollow base when in the vertical operatingorientation such that liquid leaking from the lower end of the mainchamber collects in the hollow base, and a liquid detector located inthe hollow base and operative to send a leak signal to a leak indicatorwhen liquid is detected in the hollow base.
 12. The system of claim 11wherein the hollow base is removable to provide access to repair leaksin the lower end of the main chamber.
 13. The system of claim 1 whereina floor of each silo slopes to the outlet port.
 14. The system of claim13 wherein each silo has a lower outlet port and an upper outlet portabove the lower outlet port and wherein a floor of each silo slopes tothe lower outlet port.
 15. The system of claim 1 comprising a lowerscrubber operative to direct a pressurized stream of liquid on lowerportions of an inner surface of the main chamber.
 16. The system ofclaim 1 comprising an upper scrubber operative to direct a pressurizedstream of liquid on upper portions of an inner surface of the mainchamber.
 17. The system of claim 15 wherein at least one of the upperand lower scrubbers comprises a plurality of rotating nozzles, and ahigh pressure liquid source connected to the nozzles to rotate thenozzles and provide the pressurized stream of liquid.
 18. A water siloapparatus adapted to be moved on a transport vehicle in a horizontaltransport orientation to a work site and moved to a vertical operatingorientation at the work site, the apparatus comprising: an elongate mainchamber with an outlet port in a lower portion thereof; a hollow baseattached to a lower end of the main chamber, wherein an entirety of thelower end of the main chamber rests on the hollow base when in thevertical operating position such that liquid leaking from the lower endof the main chamber collects in the hollow base; a liquid detectorlocated in the hollow base and operative to send a leak signal to a leakindicator when liquid is detected in the hollow base; an overflowchamber extending upward from a top end of the main chamber, theoverflow chamber having a cross-sectional area that is less than about20% of a cross-sectional area of the main chamber; and a vent opening inan upper portion of the overflow chamber.
 19. The apparatus of claim 18wherein the hollow base is removable to provide access to repair thelower end of the main chamber.
 20. The apparatus of claim 18 furthercomprising an aeration conduit extending from a lower portion of themain chamber to an aeration chamber located above the main chamber, anda pump operative to pump liquid from the lower portion of the mainchamber into the aeration chamber above a level of liquid in theaeration chamber.
 21. The apparatus of claim 20 wherein the aerationchamber is provided by the overflow chamber.
 22. The apparatus of claim18 wherein a floor of the silo slopes to the outlet port.
 23. Theapparatus of claim 22 wherein the silo has a lower outlet port and anupper outlet port above the lower outlet port and wherein the floorslopes to the lower outlet port.
 24. The apparatus of claim 18comprising a lower scrubber operative to direct a pressurized stream ofliquid on lower portions of an inner surface of the main chamber. 25.The apparatus of claim 24 comprising an upper scrubber operative todirect a pressurized stream of liquid on upper portions of an innersurface of the main chamber.
 26. The apparatus of claim 25 wherein atleast one of the upper and lower scrubbers comprises a plurality ofrotating nozzles, and a high pressure liquid source connected to thenozzles to rotate the nozzles and provide the pressurized stream ofliquid.